1. Field of the Invention
The present invention relates to a signal processing scheme, and more particularly to a receiver and a transmitter capable of simultaneously receiving and transmitting discontinuous frequency band signal components of an input signal and methods thereof.
2. Description of the Prior Art
Generally speaking, a conventional transceiver configuration mainly comprises a direction conversion transceiver configuration and a two-step conversion transceiver configuration. For example, U.S. Pat. No. 5,878,332 disclosed a transceiver implemented with two antennas wherein one antenna is used for receiving and transmitting signals of a band and the other antenna is used for receiving and transmitting signals of another band. Band pass filters are further employed by U.S. Pat. No. 5,878,332 for receiving and transmitting signals of the two different bands, respectively. A drawback of the transceiver provided by U.S. Pat. No. 5,878,332 is that such transceiver is not able to simultaneously receive the signals of the two different bands and is not able to simultaneously transmit the signals of the two different bands. Further, U.S. Pat. No. 7,613,430 disclosed a transceiver which performs two-step down-conversion upon a received signal and appropriately selects frequencies of two different synthesizers to avoid affection of disturbing signal components, by using a radio-frequency (RF) synthesizer and an intermediate frequency (IF) synthesizer. However, such transceiver provided by U.S. Pat. No. 7,613,430 is merely used for receiving/transmitting continuous frequency band signals but cannot be utilized for receiving and transmitting signals with discontinuous frequency bands. Moreover, U.S. Pat. No. 7,266,352 disclosed using three different local oscillation frequency signals to respectively perform down-conversion upon three different frequency band signals (802.11b/g, 802.11a (low band)/j, and 802.11a (high band)) and using another local oscillation frequency signal to down-convert these down-converted signals into baseband domain. U.S. Pat. No. 7,266,352 disclosed using a similar signal transmission scheme to perform two-step up-conversion to obtain three different frequency band signals. However, this reception/transmission circuit configuration cannot simultaneously process discontinuous frequency band signals at the same time.
As a result, it is necessary for the above-mentioned transceivers to receive discontinuous frequency band signals at different and separate timings and to transmit/emit discontinuous frequency band signals at different and separate timings.